DC Arc flashes
Increased use of batteries, hydrogen systems, electric vehicles and frequency converters for drives has led to more direct current (DC) installations. However, regulations and standards are not always prepared for this. Standardisation is still in its infancy, so customisation is often required. Arc flash calculations offer the possibility to validate installation safety.
Difference between AC and DC electric arcs
With alternating current (AC), the current changes direction 50 times per second. Current 'stands still' 100 times per second - a 'zero crossing' in technical terms. At these moments, AC current is relatively easy to interrupt. With DC, the direction of the current does not change. It continues to flow uninterrupted, making disconnection more difficult.
DC systems fed by inverters usually have only a limited short-circuit capacity, as a result of which the arc flash extinguishes relatively quickly. However, this does not apply to DC systems powered by batteries! Here, high short-circuit currents can occur.
DC arc calculations for battery systems
Battery systems are DC. The size of the arc flash depends on the battery state: is it charged, empty, somewhere in between? Working on battery systems carries an inherent risk: there is always a charge on the cells. Arc flash calculations provide insight into the risks and help determine which PPE can offer protection in the event of an accident.
Solar Panel Arc Flashes
Solar panels are DC components, so there is a risk of arc flashes. Especially when poor connectors or damaged cables are involved, the risk of fire is considerable. Because the power involved is relatively small, these are not explosive arcs. With an Arc Flash Detection (AFD) system, arc flashes can be detected. In ATEX (explosive risk) environments, timely detection and shutdown is particularly important.
The energy transition means new technologies such as solar panels and battery systems are becoming standard. These are mostly direct current-based. Arc flash simulations allow inventarization of the risks involved in working with this technology. This offers the opportunity to make adequate preparations.
Take a look at our arc flash cases!
